HAEMATOCOCCUS PLUVIALIS

Description

It is a freshwater green alga belonging to the family of hematococaceae. It is distributed worldwide, except in Antarctica, and is found in a wide variety of freshwater habitats. It is a unicellular, biflagellate alga, with its cells encapsulated by an ovoid, ellipsoid or practically spherical wall. Most of the protoplast is internally separated from the cell wall, to which it is connected by thin threads that may be simple or branched, and has two equal, apical flagella that penetrate the cellulose wall. Other structures are cup-shaped or tubular chloroplasts, the nucleus located in the chloroplast and many contractile vacuoles.

H. pluvialis presents a life cycle with different cell forms responding to environmental stimuli: vegetative form (green, with presence of flagella), palmella (green, spherical without flagella) and aplanospore (red, spherical without flagella), being this last form where astaxanthin is produced in response to hostile environmental conditions. The aplanospore then functions as a structure of resistance to adverse environmental conditions (excess salinity, high energy radiation, extreme cold, lack of nutrients, desiccation, toxins, etc.). If the environment ceases to be "hostile" the microalga is able to reverse the process by returning to the vegetative configuration, making these characteristics cyclic.

Chemical composition

The chemical composition varies depending on the form in which it is found: green (vegetative) or red (aplanospore), with proteins predominating in the green vegetative form, and lipids and carbohydrates in the red or aplanospore form.

• Proteins: the protein content is higher in the green vegetative form (29-45%) than in the red form (17-25%).
• Carbohydrates: 15-17% in the green form; 36-40% in the red form.
• Lipids: 20-25% in the green form, which increases to 32-37% in the red form. Among the lipids, phospholipids stand out: 23.7% and 21% and glycolipids: 11.5% and 26% in the green or red algae, respectively. Both forms contain neutral lipids: 59% (green algae) and 53-53% (red algae).
• Carotenoids: in green algae, the highest carotenoid content corresponds to lutein (75-80%), followed by beta-carotene (10-20%). Other secondary carotenoids are represented by chlorophyll a and b, violaxanthin, neoxanthin, zeaxanthin, etc. 

In red algae there is a significant increase in the total content of carotenoids as a response to hostile environmental factors, being characteristic the change that occurs in the profile of these compounds with respect to the green form. In this resistance phase of the algae, secondary carotenoids predominate, mainly astaxanthin, which constitutes 80-99% of them, while in the green algae it is not detected.

H. pluvialis is a natural source of astaxanthin that is currently cultivated to obtain this compound used as a supplement for its health benefits.

Pharmacological action

The effects of astaxanthin are mainly related to its antioxidant and anti-inflammatory activity. 

• Antioxidant: the antioxidant properties of astaxanthin make it an important nutritional supplement to prevent and counteract the effects of oxidative stress and prevent premature aging of the organism.

As an antioxidant, it protects different cellular structures such as membranes, mitochondria, DNA, proteins or carbohydrates, to prevent them from deteriorating or modifying their properties.

Astaxanthin is a powerful neutralizer of singlet oxygen (one of the most dangerous oxygen radicals for cells) as well as other reactive oxygen and nitrogen species. Compared to other antioxidants, astaxanthin has been shown to be more potent than beta-carotene, vitamin C, alpha-tocopherol or lutein, among others.

The increased antioxidant capacity of astaxanthin is due to its peculiar molecular structure that allows it to be placed in a strategic location in the cell membrane, protecting it against oxidative damage both internally and externally and increasing its antioxidant potential due to its interactions with the lipid bilayer of the membrane. Astaxanthin is able to cross the blood-brain and blood-retinal barriers, thus protecting the brain and retina, which are particularly susceptible to oxidative stress.

• Anti-inflammatory: related to several mechanisms such as decreased expression or production of inflammatory mediators and cytokines by suppression of nuclear factor kappa b NF-kB, neutralization of inflammatory mediators (prostaglandin E2, tumor necrosis factor alpha, interleukin 1 β, nitric oxide), inhibition of COX-2 enzyme.
• Immunostimulant: stimulates lymphocyte proliferation, increases the cytotoxic activity of NK cells, increases the production of antibody-producing B lymphocytes, activates phagocytosis, blocks the production of interferon gamma.
• Cardiovascular action: prevents oxidation of LDL ("bad cholesterol"), reduces triglyceride levels and increases HDL ("good cholesterol"), has antihypertensive action (decreases the activity of the renin-angiotensin system). These actions contribute to prevent atherosclerosis and improve cardiovascular health.
• Action on the nervous system: astaxanthin has a neuroprotective effect against degenerative diseases such as Alzheimer's, Parkinson's, dementia, amyotrophic lateral sclerosis (ALS), senility, etc.
• Ocular action: improves visual acuity, reduces eye fatigue, prevents the onset of cataracts, glaucoma, age-related macular degeneration (AMD), retinopathy (hypertensive, diabetic).
• At the cutaneous level: protects against the harmful effects of ultraviolet radiation on the skin, prevents skin aging due to exposure to sunlight, the appearance of spots, collagen degradation, phototoxicity and photoallergy. It protects the DNA of skin cells.
• At the digestive level: inhibits the growth of Helicobacter pylori and improves dyspeptic symptoms, protects the gastric mucosa from the irritating action of some anti-inflammatory drugs and alcohol.
• At the sports level: protects muscle cells from free radical damage produced during exercise, improves performance and muscular endurance, accelerates muscle recovery after intense effort, reduces fatigue and muscle or joint pain that may appear after exercise.
• Other actions: hepatoprotective, improves fertility, antitumor, in diabetes improves insulin resistance and glucose tolerance, increases insulin production and prevents the development of diabetic nephropathy.

Indications

• Ocular health: people who spend a long time in front of electronic screens, night blindness, habitual night driving, practice of water or snow sports (sun protection), prevention and adjuvant in the treatment of cataract, glaucoma, age-related macular degeneration, retinopathies, etc.).
• Skin care.
• Prevention and adjuvant in the treatment of neurodegenerative diseases.
• Sportsmen.
• Gastritis or peptic ulcer.
• Diabetics.
• Prevention and coadjuvant in the treatment of cardiovascular diseases.

Contraindications

Pregnancy and lactation.

Precautions

No special precautions at the recommended doses.

Drug interactions

None have been described at recommended doses.

Side effects

None have been described at recommended doses.

Bibliographic references

-.Córdoba-Castro, NM., Acero-Reyes, N.L., Duque-Buitrago, L.F., Jiménez-Aguilar, L.J., Serna-Jiménez, J.A. (2015) Obtención y caracterización de astaxantina de la microalga Haematococcus Pluvialis. UGCiencia 21, 73-82.

-.Ming Xian Chang, Fan Xiong. Astaxanthin and its effects in inflammatory responses and inflammation-associated diseases. Recent advances and future directions. Molecules 2020, Nov; 25(22): 5342.

-.P. López Roldán, N. Mach. Efecto del consumo de astaxantina en la salud. Rev Esp Nutr Comunitaria. 2012;18(3):162-175.

-.Ranga Rao Ambati, Phang Siew Moi, Sarada Ravi, Ravidhankar Gokare Aswathanarayana. Astaxanthin: sources, extraction, stability, biological activities and its commercial applications. A review. Mar Drugs 2014 Jan; 12(1): 128–152.

-.Kidd P. Astaxanthin, cell membrane nutrient with diverse clinical benefits and anti-aging potential. Altern. Med. Rev. 2011;16:355–364.

-.Galasso C., Orefice I., Pellone P., Cirino P., et al. On the Neuroprotective Role of Astaxanthin: New Perspectives? Mar. Drugs. 2018;16:247.

-.Davinelli S., Nielsen M.E., Scapagnini G. Astaxanthin in Skin Health, Repair, and Disease: A Comprehensive Review. Nutrients. 2018;10:522.

-.M. R. Shah, Y. Liang, J. Cheng, 2 and M. Daroch. Astaxanthin producing green microalga Haematococcus pluvialis: from single cell to high value commercial products. Frontiers in Plant Science. Apriil 2016, vol 7. Article 531.